Efficient Sulphate Reduction by Cellulolytic and Sulphate-Reducing Bacterial Co-Culture Using Different Agro-Industrial Wastes as Growth Substrates

Abstract

Aquatic resources are being devastating rapidly due to the continuous intrusion of untreated wastes into the environment due to rapid industrialization and causing severe problems to aquatic life. Different physicochemical methods have been used to reduce these pollutants but all have their own limitations including production of secondary pollutants. The current study was designed to show the effect of cellulolytic and sulphate-reducing bacterial species in the form of a co-culture to treat an in-vitro prepared sulphate-rich wastewater while employing various agro-industrial organic waste as economical growth substrates. A combination of sulphate-reducing and cellulolytic bacteria in a ratio of 1:1 (v/v) was proved to be efficient for the reduction of sulphate in controlled as well as in the experimental conditions. The implicated microbial co-culture reduced 96 and 93 % of the added sulphate (5 gL −1 ) while using rice straw and animal manure, respectively in a 60-day trial of anaerobic incubation. Mixture of industrial and agricultural waste reduced about 90 % of the total added sulphate. A trend of decrease in pH with time was observed in all the incubated cultures. Our findings will be helpful for devising sustainable waste management strategies.